Rising stem soft seat plug valve

ABSTRACT

A rising stem plug valve has a valve body housing that receives a plug. A handle assembly is attached to the plug for rotational movement of the plug between operative positions. A control assembly is attached to the plug for unseating and seating of the plug within the valve body. The plug includes at least one plug portion having openings corresponding to an interior configuration. Ring cords substantially surround the openings in the plug to create a seal therearound. The plug may include upper and lower plug portions with an untapered portion located between them. An O-ring is located on the untapered portion of the plug to maintain separation between the upper and lower plug portions.

This application is a continuation of U.S. patent application Ser. No.09/469,417 entitled “Rising Stem Soft Seat Plug Valve” filed Dec. 23,1999, now U.S. Pat. No. 6,196,268.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a plug valve, more particularly, to a risingstem single or dual (i.e., stacked) plug valve of the type typicallyused in dual canister strainer assemblies and as diverter valves.

2. Description of the Prior Art

Plug valves are quite well-known in the art. U.S. Pat. Nos. 2,215,853and 2,893,681 both to McNeal teach stacked tapered plug valves fortwo-canister strainers. Stacked, simultaneously operated tapered valveswherein each valve member has an individual taper are disclosed in U.S.Pat. Nos. 3,595,270 to McNeal, Jr. and 3,679,060 to Smith.

U.S. Pat. Nos. 3,499,467 to McCord et al.; 3,768,654 to Pearce;4,355,659 to Kelchner; and 5,102,543 to Burroughs teach a variety ofstacked valves having O-rings or other sealing members positionedbetween the two valves to maintain a sealing separation between theseelements.

The General Twin Seal™ valve by General Valve Company is a rising stemstacked plug valve having seating slips mounted independently on thetapered plug. The seating slips have O-rings located on the outersurface which interact with the valve body to create a seal. The slipshave openings that correspond to the plug valve openings. The O-ringsare forced into contact with the valve body during seating of the plug.The slips create a double seal around the openings through O-ringcontact and metal to metal contact.

The prior art teaches rising stem plug valves wherein each valve istapered. However, in a rising stem dual plug valve it is undesirable tolocate an O-ring for sealing separation between the plug valves andtapered portion of the plug body between the individual valves.

Most of the prior art relies on surface to surface contact of the plugand the valve body to create a seal around the plug openings. Forexample, consider U.S. Pat. No. 2,001,035 to Noll illustrating aconventional metal to metal seal for a plug valve. When both bodies aremetal, this seal is not always adequate. The General Twin Seal™ valverelies not only on surface to surface contact, but also on O-rings.However, the O-rings are located on an independent slip thatcommunicates with the plug and valve body. U.S. Pat. No. 4,726,391 toBarra discloses a complex valve in which each part is surrounded bygrooves which receive U-shaped sealing members. The U-shaped sealingmembers include a passage to transmit leakage. The passage minimizes thetotal sealing area of the sealing member. The U-shaped sealing memberalso includes open areas adjacent the valve body to allow fordeformation of the sealing portions. These open spaces minimize thesupport or backing for the sealing portions.

Conventional rising stem plug valves utilize a handle or wheel to raiseand lower a stem coupled to the plug in order to unseat and seat theplug within the valve body. While this is practical in someapplications, the degree of freedom is somewhat limiting.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a rising stem plug valveassembly comprising an improved seal around each opening in the plug.

It is a further object of the present invention to provide a rising stemdual plug valve wherein the plug comprises an untapered portion betweenthe upper and lower portions of the plug.

It is yet another object of the present invention to provide a greaterdegree of freedom for raising and lowering the plug during unseating andseating of the plug(s) into a valve housing.

The valve assembly of the present invention is a rising stem plug valveincluding a valve housing, a plug(s), a handle for rotating the plugbetween operative positions in a conventional fashion, a stem, and anassembly for unseating and seating the plug within the valve housing.The valve assembly may be a rising stem single plug valve wherein theplug has plug openings to form at least one valve that may be a taperedplug valve. The valve assembly may be a rising stem dual plug valvewherein the plug has integrally formed upper and lower portions each ofwhich have plug openings and may be tapered forming a tapered plugvalve.

In the rising stem dual plug valve of the instant invention, positionedbetween the upper and lower portions of the plug is an O-ring on astraight, untapered portion of the plug. The O-ring maintains fluidseparation between the upper and lower portions of the plug, even as theplug is raised.

A control assembly, for example a ratcheting assembly, is coupled to thestem, for example a threading screw. The stem is in turn coupled to theplug. This construction allows for the unseating and seating of the plugwithin the valve body.

Sealing ring cords, preferably rectangular in cross-section,substantially surround each plug opening thereby creating an improvedseal around each opening.

The plug interior pattern between the plug openings of the presentinvention may be one of many cross-sectional configurations to allow fordifferent flow patterns depending on the application of the valveassembly. In the rising stem dual plug valve of this invention, theupper and lower portions of the plug may have different interiorconfigurations.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and other objects and advantages will become apparentfrom the following detailed description made with reference to thedrawings in which:

FIG. 1 is a front sectional view of a valve assembly illustrating arising stem dual plug valve embodiment according to the presentinvention;

FIG. 2 is a top plan view of the valve assembly in FIG. 1 as used inconjunction with a dual canister strainer assembly;

FIG. 3 is a front sectional view of a valve assembly depicting a risingstem single plug valve embodiment according to the present invention;and

FIGS. 4a-4 d are a series of cross-sectional views representing examplesof interior configurations of the plug showing the ring cords around theplug openings in the preferred rectangular cross-sectionalconfiguration.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a valve assembly 100 according to a firstembodiment of the present invention is a rising stem dual plug valve.The valve assembly 100 includes a valve housing 110, a plug 112, and ahandle assembly 114. The valve housing 110 is adapted to receive theplug 112 therein. The handle assembly 114 is coupled to the plug 112 tofacilitate rotational movement of the plug 112 between operativepositions in a conventional manner. The plug 112 is preferablyconstructed of stainless steel or bronze.

The plug 112 is comprised of integrally formed upper and lower plugportions 116 and 118, respectively, that each contain a plurality ofopenings 120. The number and location of openings 120 are such toaccommodate the necessary interior configuration of the plug portions116 or 118 to achieve the desired flow pattern. FIGS. 4a-4 d (discussedbelow) depict exemplary cross-sectional configurations of plug portion116 and 118 interiors.

In a preferred embodiment, the upper and lower plug portions 116 and118, respectively, are tapered. The tapering of the plug portions 116and 118 reduces the amount of drag during movement between operativepositions. The angle of taper of the upper plug portion 116 may bedifferent than that of the lower plug portion 118.

A threading screw 124 is coupled to the plug 112. A control assembly 126is coupled to the threading screw 124 to provide axial movement of thethreading screw 124 for the unseating and seating of the upper and lowerplug portions 116 and 118, respectively, within the valve housing 110.In the embodiment of FIG. 1, the assembly 126 is a reversible ratchetingassembly. As shown in FIG. 2, the ratcheting assembly includes an arm127 connected to a control nut 125 through a conventional ratchetconnection (not shown). The control nut 125 is coupled to the threadingscrew 124 such that rotation of the control nut 125 will result in axialmotion of the threading screw 124 with the direction of the axial motionof the threading screw 124 determined by the direction of rotation ofthe control nut 125. As apparent to those skilled in the art, pivotingor rotation of the arm 127 will cause rotation of the control nut 125 inonly one direction through the action of the ratchet connection. The“drive” direction of the ratchet connection can be selectively switchedto change the direction of rotation of the control nut 125.

In FIG. 1, the upper and lower plug portions 116 and 118, respectively,are separated by an untapered (i.e., straight side in cross-section)portion 122 of the plug 112. An O-ring 128 is located on the untaperedportion 122 of the plug body 112 to maintain sealing separation betweenthe upper and lower plug portions 116 and 118, respectively, even as theplug 112 is raised and lowered during unseating and seating of the upperand lower plug portions 116 and 118, respectively.

The valve assembly 100 further includes a plurality of upper and lowerring cords 130 and 132, respectively. Each upper ring cord 130 islocated such that an upper ring cord 130 substantially surrounds eachopening 120 on the upper plug portion 116 to provide a seal therearound.Likewise, each lower ring cord 132 is located such that a lower ringcord 132 substantially surrounds each opening 120 on the lower plugportion 118 to provide a seal therearound. Preferably, the plurality ofupper and lower ring cords 130 and 132, respectively, have a rectangularcross-sectional configuration. The ring cords 130 and 132 improve theseal around the openings 120, more so when the valve body 110 and theplug body 112 are both preferably constructed of metal.

FIG. 3 depicts another embodiment of the present invention wherein avalve assembly 200 is a rising stem single plug valve. The valveassembly 200 includes a valve housing 210, a plug 212, and a handleassembly 214. The valve housing 210 is adapted to receive the plug 212therein. The handle assembly 214 is coupled to the plug 212 tofacilitate rotational movement of the plug 212 between operativepositions in a conventional manner. The plug 212 is preferablyconstructed of stainless steel or bronze.

The plug 212 is comprised of a single plug portion 217 which forms onlya single plug valve. The plug portion 217 contains a plurality ofopenings 220. The number and location of openings 220 are such toaccommodate the necessary interior configuration of the plug portion 217to achieve the desired flow pattern. FIGS. 4a-4 d (discussed below)depict exemplary cross-sectional configurations of plug portion 217interiors.

In a preferred embodiment, the plug portion 217 is tapered. The taperingof the plug portion 217 reduces the amount of drag during movementbetween operative positions.

A threading screw 224 is coupled to the plug 212. A control assembly 226is coupled to the threading screw 224 to provide axial movement of thethreading screw 224 for the unseating and seating of the plug portion217 within the valve housing 210. In the illustrated embodiment, theassembly 226 is a ratcheting assembly substantially the same as theratcheting assembly shown in FIG. 1. The ratcheting assembly includes acontrol nut 225 engaging the threading screw 224 and an arm 227connected to the control nut 225 through a ratcheting connection (notshown).

The valve assembly 200 further includes a plurality of ring cords 231.Each ring cord 231 is located such that a ring cord 231 substantiallysurrounds each opening 220 on the plug portion 217 to provide a sealtherearound. Preferably, the plurality of ring cords 231 each have arectangular cross-sectional configuration. The ring cords 231 improvethe seal around the openings 220, more so when the valve housing 210 andthe plug 212 are both constructed of metal, which is preferred.

FIGS. 4a-4 d depict exemplary embodiments 310, 312, 314, and 316 ofcross-sectional configurations of plug portions 116, 118 or 217interiors. Embodiment 310 of FIG. 4a shows an elbow configuration,embodiment 312 of FIG. 4b illustrates a straight configuration,embodiment 314 of FIG. 4c depicts a double elbow configuration, andembodiment 316 of FIG. 4d shows a tee configuration. It would be obviousto one skilled in the art to construct the present invention such thatother cross-sectional configurations are utilized. The embodiments 310,312, 314 and 316 include rectangular ring cords 318 substantially thesame as ring cords 130, 132 and 231 discussed above with ring cords 318surrounding the plug valve openings. The rectangular ring cords 318,231, 132 and 131 provide greater surface area to increase the contactarea of the ring cords 318, 231, 132 or 131 and improve the seal overconventional circular sealing members.

It will be understood by those skilled in the art that while theforegoing description sets forth in detail preferred embodiments of thepresent invention, modifications, additions, and changes might be madethereto without departing from the spirit and scope of the invention.The foregoing embodiments are merely illustrative of the presentinvention and not restrictive thereof. The scope of the presentinvention is set forth in the following claims and equivalents thereto.

We claim:
 1. A valve assembly comprising: a valve housing; a plugreceived in the valve housing, the plug having at least one plug portionwith a plurality of openings corresponding to the interior configurationof the plug portion; a plurality of ring cords on the plug, each of thering cords substantially surrounding one of the plurality of openings,wherein each ring cord is a substantially rectangular ring cord having asealing surface extending substantially the entire width of the ringcord and a surface opposite the sealing surface being immediatelyadjacent the plug for substantially the entire width of the ring cord,wherein the plug has an upper and lower plug portion and an untaperedportion between said upper and lower plug portion; an O-ring located inthe untapered portion of the plug; and a control assembly coupled to theplug for axial movement thereof.
 2. A valve assembly according to claim1, wherein the upper and lower plug portions are integrally formed.
 3. Aplug assembly according to claim 1 wherein each plug portion is tapered.4. A valve assembly according to claim 3, wherein the control assemblyincludes a ratchet assembly, wherein the ratchet assembly has aselectable drive direction wherein the selected drive direction willcontrol the axial movement of the plug.
 5. A rising stem plug valvecomprising: a valve housing; a plug received in the valve housing, theplug having an upper and lower integrally formed tapered plug portion,each tapered plug portion having a plurality of openings therein,wherein the plug valve has an untapered portion between said upper andlower plug portion and an O-ring located in the untapered portion of theplug; a threading screw attached to the plug; a control nut engaging thethreading screw; and a ratchet assembly attached to the threading screwfor axial movement of the plug without rotational movement of the plug,wherein the ratchet assembly will cause rotation of the control nut inonly one selected drive direction through action of the ratchet assemblyand wherein the drive direction of the ratchet assembly can beselectively switched to change the drive direction of the control nut.6. A rising stem plug valve according to claim 5, further including aplurality of cross-sectionally rectangular ring cords, each ring cordsubstantially surrounding one of the plurality of openings and sealingdirectly against the valve housing.
 7. A rising stem plug valveaccording to claim 5, further including a handle coupled to the plug forrotating the plug between operative positions.
 8. A rising stem plugvalve according to claim 5, wherein an interior configuration of atleast one plug portion is a tee.
 9. A rising stem plug valve accordingto claim 5, wherein an interior configuration of at least one plugportion is an elbow.
 10. A rising stem plug valve according to claim 5,wherein an interior configuration of the at least one plug portion isstraight.
 11. A rising stem plug valve according to claim 5, wherein aninterior configuration of the at least one plug portion is a doubleelbow.
 12. A rising stem plug valve according to claim 5, wherein aninterior configuration of the upper plug portion is different than aninterior configuration of the lower plug portion and the tapered upperand lower plug portions each have a different degree of taper.
 13. Arising stem plug valve according to claim 5, further including an armfor rotating the control nut through the ratchet assembly.
 14. A valveassembly according to claim 2, wherein the control assembly includes aratchet assembly.